Addressing 14 health and lifestyle factors could prevent nearly half of global dementia cases

It was a milestone: the first major global consensus on the preventable nature of dementia, suggesting that around a third of cases were linked to these factors.

Back in 2017, a team of researchers published a landmark report. After looking over decades of meticulous research, they’d concluded that there was sufficient evidence that dementia was linked to nine lifestyle and environmental risk factors.

It led us to launch our Think Brain Health campaign, to help people understand what they could do to reduce their risk.

Three years later, in 2020, the researchers updated their report in light of new evidence, adding three new risk factors to the list, and suggesting that around 40% of cases were linked to these so-called ‘modifiable’ risk factors.

Today, at this year’s Alzheimer’s Association International Conference in the US, the team has revealed their latest analysis, which Alzheimer’s Research UK is proud to have helped fund.

They’ve now updated the list of confirmed dementia risk factors to 14. That’s two more than previously recognised.

Taken together, the researchers calculate that these 14 risk factors account for almost half (45%) of all dementia cases around the world.

That means there’s a huge opportunity to stop dementia before it ever starts.

Because this news will likely make the headlines, we know it’ll raise lots of questions. So we’ve put together some key information on what these findings mean, things we can all do to help protect our brain health, and role that the government needs to play to help tackle the risk factors that are beyond our control.

To get started, here’s a clip of the study’s lead author – UCL’s Prof Gill Livingston – explaining the report’s key findings:

What is a dementia risk factor?

A risk factor is something that affects the likelihood of something happening to us, such as developing a condition like dementia.

There are certain things that influence dementia risk that we can’t control – such as our age, and the genes we inherit. Researchers call these ‘non-modifiable’ risk factors.

On the other hand, ‘modifiable’ risk factors are those that we as individuals, or that policymakers such as the government, can influence.

What does the latest Lancet Commission tell us?

Around the world, researchers are studying all sorts of potential dementia risk factors, publishing literally thousands of studies every year. To make sense of all this emerging evidence, twenty-seven world leading dementia experts came together for the third instalment of the Lancet Commission on dementia prevention, intervention and care.  Reviewing the latest evidence on the factors that affect our risk of developing dementia, they’ve now established two new risk factors, taking the list from 12 to 14.

The 14 risk factors are:

• Quality of education in early life
• Social isolation
• Air pollution
• Traumatic brain injury
• Hearing loss
• Depression
• High blood pressure
• Diabetes
• Obesity
• Physical inactivity
• Smoking
• Excessive alcohol consumption
• Uncorrected vision loss
• High cholesterol

The researchers calculate that if, as a society and as individuals, we could completely address these 14 health and lifestyle factors it could prevent or delay nearly half (45%) of dementia cases.

It’s important to note that this doesn’t mean that individual cases can be attributed to either ‘lifestyle’ or ‘non-lifestyle’ factors. Just as we are all affected by both the genes we’re born with and the lives we lead, our chances of developing dementia are influenced by both too. And there’s no sure-fire way of preventing it.

What this research is saying is that dementia is more common among people who have one or more of these risk factors.

How did the researchers identify these 14 risk factors?

Risk factors for different conditions, including dementia, are usually identified through studies known as observational studies. These are where data from a large group of people are collected over long periods of time to see who did or didn’t go on to develop dementia.

Researchers can then look at whether certain behaviours or conditions are linked to a diagnosis of dementia.

Because dementia takes a long time to develop, and is influenced by risk factors that affect us throughout our lives, these observational studies are key to revealing potential risk factors for dementia. But they’re not perfect – they don’t reveal how particular risk factors are linked to the condition, nor what is happening in the brain to causes these changes.

In drawing up the Lancet report, the researchers pulled together data from hundreds of observational studies across the globe. Using statistical calculations, they were able to estimate the size of impact of the 14 risk factors, and the percentage of cases that would be prevented or delayed if each risk factor didn’t exist.

They then combined these results, taking into account how some people tend to have more than one risk factor, leading to the figure of 45%.

What are the two new dementia risk factors?

In the updated report, the researchers conclude that there’s now sufficient evidence to add two new risk factors— uncorrected vision loss and high cholesterol.  They calculate that, taken together, these are associated with 9% of all dementia cases

Uncorrected vision loss covers lots of things, including not wearing glasses for short- or long-sightedness over a very long period of time. But of particular note, research has identified an increase in dementia risk among people with two specific conditions that cause vision loss – diabetic retinopathy and cataracts – if they go untreated. More research is needed to understand exactly why these increase risk, but these eye conditions are linked to inflammation and blood vessel damage, which contribute to diseases like Alzheimer’s.

High cholesterol is a common, treatable condition that increases the risk of several other serious conditions, including strokes and blood vessel damage. Nearly one in three people who have a stroke go on to develop vascular dementia, highlighting how high cholesterol may at least in part contribute to dementia risk. There are also studiers suggesting that it may be linked to a build-up of proteins called amyloid and tau – both of which are key features of Alzheimer’s disease.

The new report estimates that the most important risk factors, linked to the greatest proportion of people developing dementia, are hearing impairment and high cholesterol (7% each) followed by less education in early life and social isolation in later life (5% each).

What can I do to protect my brain health?

Our latest Dementia Attitudes Monitor shows that only a third of the UK public think it’s possible to reduce the risk of developing dementia.

But as the Lancet Commission’s findings show, dementia isn’t an inevitable part ageing, and there are things we can all do to reduce our risk of developing dementia in the future.

Alzheimer’s Research UK’s three rules for good brain health are:

• love your heart
• stay sharp
• keep connected.

If you’re looking for some inspiration on how to protect your brain health, why not try our Think Brain Health Check in? And we’ve just updated it with the new evidence – so worth doing again, even if you have before.

At what age should I start looking after my brain health?

First things first – it’s never too early or too late to start looking after your brain health.

The Lancet report found that addressing dementia risk factors are important at different stages of life. For example, managing hearing loss is important from midlife – approximately when you turn 40 – whereas trying to stay connected to those around you seems to be more important later on.

The good news is that this provides a huge opportunity to take steps throughout our lives to keep our brains healthy and lessen the devastating impact of dementia on our society and our loved ones in future. There’s more on our Think Brain Health hub.

What should the government do to protect the nation’s brain health?

We have control over many of the dementia risk factors, like giving up smoking. But others, like air pollution and early childhood education, are beyond our control. Tackling them will need structural changes to society to give everyone the best chance of a healthy life, free from the impact of dementia. And public health leaders must not ignore this message if they are truly committed to seizing this enormous opportunity.

At Alzheimer’s Research UK, we want to see the new Public Health and Prevention Minister, Andrew Gwynne MP, establish a prevention strategy that addresses the health and lifestyle factors linked to dementia – from what we eat and drink, to the air we breathe and the education we receive.

A similar strategy was adopted by the previous Labour government, aimed at reducing health inequalities between the most deprived local authorities and the rest of England. After the plan was put in place, life expectancy improved in areas across England where it had been lower compared to other areas.

If you’d like to stand with us and make sure the government takes action, then make sure you’re signed up to our campaigner network.

Are Alzheimer’s Research UK supporting research into prevention?

So far, Alzheimer’s Research UK has funded over £10 million of research into looking at how we can reduce dementia risk groundbreaking projects. This includes supporting initiatives like the Lancet Commission, but also researchers around the country. To take just a couple of examples, at UCL, Prof Jason Warren’s is exploring the links between hearing loss and dementia, and how hearing issues might signal or even increase dementia risk. Meanwhile, at the University of Dundee, Dr Fiona McLean is delving into the blood-brain barrier, studying how diet and energy use, particularly in diabetes, can affect this crucial brain shield and raise dementia risk.

You can hear both of them talking about their work at our next free Online Public Event on Tues 24^th September. Sign up here.

Dementia has devastated too many lives already. It’s vital that we continue finding ways to prevent people from ever developing the condition in the first place. And as part of Alzheimer’s Research UK’s mission for a cure, we’ll continue to do just that.